[alsa-devel] ASoC: nau8825: improve semaphore control
After reviewing the crosstalk protection, there are two flaws at semaphore control. The first one is that the semaphore releases are not enough; and the other is that down_interruptible has an risk to make the ISR sleep. Therefore, the driver add more releases before the funcitons return. Take down_trylock to replace down_interruptible. The ISR can control the protection as well and never sleep by semaphore.
Signed-off-by: John Hsu KCHSU0@nuvoton.com --- sound/soc/codecs/nau8825.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-)
diff --git a/sound/soc/codecs/nau8825.c b/sound/soc/codecs/nau8825.c index 7947b11..2aea642 100644 --- a/sound/soc/codecs/nau8825.c +++ b/sound/soc/codecs/nau8825.c @@ -245,13 +245,14 @@ static const unsigned short logtable[256] = { * tasks are allowed to acquire the semaphore, calling this function will * put the task to sleep. If the semaphore is not released within the * specified number of jiffies, this function returns. - * Acquires the semaphore without jiffies. If no more tasks are allowed - * to acquire the semaphore, calling this function will put the task to - * sleep until the semaphore is released. * If the semaphore is not released within the specified number of jiffies, - * this function returns -ETIME. - * If the sleep is interrupted by a signal, this function will return -EINTR. - * It returns 0 if the semaphore was acquired successfully. + * this function returns -ETIME. If the sleep is interrupted by a signal, + * this function will return -EINTR. It returns 0 if the semaphore was + * acquired successfully. + * + * Acquires the semaphore without jiffies. Try to acquire the semaphore + * atomically. Returns 0 if the semaphore has been acquired successfully + * or 1 if it it cannot be acquired. */ static int nau8825_sema_acquire(struct nau8825 *nau8825, long timeout) { @@ -262,8 +263,8 @@ static int nau8825_sema_acquire(struct nau8825 *nau8825, long timeout) if (ret < 0) dev_warn(nau8825->dev, "Acquire semaphore timeout\n"); } else { - ret = down_interruptible(&nau8825->xtalk_sem); - if (ret < 0) + ret = down_trylock(&nau8825->xtalk_sem); + if (ret) dev_warn(nau8825->dev, "Acquire semaphore fail\n"); }
@@ -1258,8 +1259,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, regmap_read(nau8825->regmap, NAU8825_REG_DAC_CTRL1, &osr); osr &= NAU8825_DAC_OVERSAMPLE_MASK; if (nau8825_clock_check(nau8825, substream->stream, - params_rate(params), osr)) + params_rate(params), osr)) { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER, NAU8825_CLK_DAC_SRC_MASK, osr_dac_sel[osr].clk_src << NAU8825_CLK_DAC_SRC_SFT); @@ -1267,8 +1270,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, regmap_read(nau8825->regmap, NAU8825_REG_ADC_RATE, &osr); osr &= NAU8825_ADC_SYNC_DOWN_MASK; if (nau8825_clock_check(nau8825, substream->stream, - params_rate(params), osr)) + params_rate(params), osr)) { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER, NAU8825_CLK_ADC_SRC_MASK, osr_adc_sel[osr].clk_src << NAU8825_CLK_ADC_SRC_SFT); @@ -1285,8 +1290,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, bclk_div = 1; else if (bclk_fs <= 128) bclk_div = 0; - else + else { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_I2S_PCM_CTRL2, NAU8825_I2S_LRC_DIV_MASK | NAU8825_I2S_BLK_DIV_MASK, ((bclk_div + 1) << NAU8825_I2S_LRC_DIV_SFT) | bclk_div); @@ -1306,6 +1313,7 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, val_len |= NAU8825_I2S_DL_32; break; default: + nau8825_sema_release(nau8825); return -EINVAL; }
@@ -1324,8 +1332,6 @@ static int nau8825_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt) struct nau8825 *nau8825 = snd_soc_codec_get_drvdata(codec); unsigned int ctrl1_val = 0, ctrl2_val = 0;
- nau8825_sema_acquire(nau8825, 3 * HZ); - switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) { case SND_SOC_DAIFMT_CBM_CFM: ctrl2_val |= NAU8825_I2S_MS_MASTER; @@ -1367,6 +1373,8 @@ static int nau8825_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt) return -EINVAL; }
+ nau8825_sema_acquire(nau8825, 3 * HZ); + regmap_update_bits(nau8825->regmap, NAU8825_REG_I2S_PCM_CTRL1, NAU8825_I2S_DL_MASK | NAU8825_I2S_DF_MASK | NAU8825_I2S_BP_MASK | NAU8825_I2S_PCMB_MASK, @@ -1713,7 +1721,7 @@ static irqreturn_t nau8825_interrupt(int irq, void *data) int ret; nau8825->xtalk_protect = true; ret = nau8825_sema_acquire(nau8825, 0); - if (ret < 0) + if (ret) nau8825->xtalk_protect = false; } /* Startup cross talk detection process */ @@ -2399,7 +2407,7 @@ static int __maybe_unused nau8825_resume(struct snd_soc_codec *codec) regcache_sync(nau8825->regmap); nau8825->xtalk_protect = true; ret = nau8825_sema_acquire(nau8825, 0); - if (ret < 0) + if (ret) nau8825->xtalk_protect = false; enable_irq(nau8825->irq);
The patch
ASoC: nau8825: improve semaphore control
has been applied to the asoc tree at
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git
All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced.
Please add any relevant lists and maintainers to the CCs when replying to this mail.
Thanks, Mark
From 70424d8e6e15abd32e189130be220d0063e082bc Mon Sep 17 00:00:00 2001
From: John Hsu KCHSU0@nuvoton.com Date: Fri, 1 Dec 2017 10:01:50 +0800 Subject: [PATCH] ASoC: nau8825: improve semaphore control
After reviewing the crosstalk protection, there are two flaws at semaphore control. The first one is that the semaphore releases are not enough; and the other is that down_interruptible has an risk to make the ISR sleep. Therefore, the driver add more releases before the funcitons return. Take down_trylock to replace down_interruptible. The ISR can control the protection as well and never sleep by semaphore.
Signed-off-by: John Hsu KCHSU0@nuvoton.com Signed-off-by: Mark Brown broonie@kernel.org --- sound/soc/codecs/nau8825.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-)
diff --git a/sound/soc/codecs/nau8825.c b/sound/soc/codecs/nau8825.c index 603cd72c2a25..5778eadbf9e6 100644 --- a/sound/soc/codecs/nau8825.c +++ b/sound/soc/codecs/nau8825.c @@ -245,13 +245,14 @@ static const unsigned short logtable[256] = { * tasks are allowed to acquire the semaphore, calling this function will * put the task to sleep. If the semaphore is not released within the * specified number of jiffies, this function returns. - * Acquires the semaphore without jiffies. If no more tasks are allowed - * to acquire the semaphore, calling this function will put the task to - * sleep until the semaphore is released. * If the semaphore is not released within the specified number of jiffies, - * this function returns -ETIME. - * If the sleep is interrupted by a signal, this function will return -EINTR. - * It returns 0 if the semaphore was acquired successfully. + * this function returns -ETIME. If the sleep is interrupted by a signal, + * this function will return -EINTR. It returns 0 if the semaphore was + * acquired successfully. + * + * Acquires the semaphore without jiffies. Try to acquire the semaphore + * atomically. Returns 0 if the semaphore has been acquired successfully + * or 1 if it it cannot be acquired. */ static int nau8825_sema_acquire(struct nau8825 *nau8825, long timeout) { @@ -262,8 +263,8 @@ static int nau8825_sema_acquire(struct nau8825 *nau8825, long timeout) if (ret < 0) dev_warn(nau8825->dev, "Acquire semaphore timeout\n"); } else { - ret = down_interruptible(&nau8825->xtalk_sem); - if (ret < 0) + ret = down_trylock(&nau8825->xtalk_sem); + if (ret) dev_warn(nau8825->dev, "Acquire semaphore fail\n"); }
@@ -1246,8 +1247,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, regmap_read(nau8825->regmap, NAU8825_REG_DAC_CTRL1, &osr); osr &= NAU8825_DAC_OVERSAMPLE_MASK; if (nau8825_clock_check(nau8825, substream->stream, - params_rate(params), osr)) + params_rate(params), osr)) { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER, NAU8825_CLK_DAC_SRC_MASK, osr_dac_sel[osr].clk_src << NAU8825_CLK_DAC_SRC_SFT); @@ -1255,8 +1258,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, regmap_read(nau8825->regmap, NAU8825_REG_ADC_RATE, &osr); osr &= NAU8825_ADC_SYNC_DOWN_MASK; if (nau8825_clock_check(nau8825, substream->stream, - params_rate(params), osr)) + params_rate(params), osr)) { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER, NAU8825_CLK_ADC_SRC_MASK, osr_adc_sel[osr].clk_src << NAU8825_CLK_ADC_SRC_SFT); @@ -1273,8 +1278,10 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, bclk_div = 1; else if (bclk_fs <= 128) bclk_div = 0; - else + else { + nau8825_sema_release(nau8825); return -EINVAL; + } regmap_update_bits(nau8825->regmap, NAU8825_REG_I2S_PCM_CTRL2, NAU8825_I2S_LRC_DIV_MASK | NAU8825_I2S_BLK_DIV_MASK, ((bclk_div + 1) << NAU8825_I2S_LRC_DIV_SFT) | bclk_div); @@ -1294,6 +1301,7 @@ static int nau8825_hw_params(struct snd_pcm_substream *substream, val_len |= NAU8825_I2S_DL_32; break; default: + nau8825_sema_release(nau8825); return -EINVAL; }
@@ -1312,8 +1320,6 @@ static int nau8825_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt) struct nau8825 *nau8825 = snd_soc_codec_get_drvdata(codec); unsigned int ctrl1_val = 0, ctrl2_val = 0;
- nau8825_sema_acquire(nau8825, 3 * HZ); - switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) { case SND_SOC_DAIFMT_CBM_CFM: ctrl2_val |= NAU8825_I2S_MS_MASTER; @@ -1355,6 +1361,8 @@ static int nau8825_set_dai_fmt(struct snd_soc_dai *codec_dai, unsigned int fmt) return -EINVAL; }
+ nau8825_sema_acquire(nau8825, 3 * HZ); + regmap_update_bits(nau8825->regmap, NAU8825_REG_I2S_PCM_CTRL1, NAU8825_I2S_DL_MASK | NAU8825_I2S_DF_MASK | NAU8825_I2S_BP_MASK | NAU8825_I2S_PCMB_MASK, @@ -1701,7 +1709,7 @@ static irqreturn_t nau8825_interrupt(int irq, void *data) int ret; nau8825->xtalk_protect = true; ret = nau8825_sema_acquire(nau8825, 0); - if (ret < 0) + if (ret) nau8825->xtalk_protect = false; } /* Startup cross talk detection process */ @@ -2383,7 +2391,7 @@ static int __maybe_unused nau8825_resume(struct snd_soc_codec *codec) regcache_sync(nau8825->regmap); nau8825->xtalk_protect = true; ret = nau8825_sema_acquire(nau8825, 0); - if (ret < 0) + if (ret) nau8825->xtalk_protect = false; enable_irq(nau8825->irq);
participants (2)
-
John Hsu -
Mark Brown